Development of protein nanoparticle based composite materials

Abstract

Inspired by the core-shell composite structures found in nature, a range of protein based composites have been developed. These materials were made using synthetic approaches, which utilized the native protein architecture as an initiation point and size constrained reaction vessel for the piecewise formation of the second material. In the first illustration of this approach, a protein-P t composite was formed, where the protein cage has been modified to include a metal binding moiety for improved synthesis of metallic P t nanoclusters, which were shown to be an active H 2 catalyst. This composite was analyzed by native mass spectrometry to determine the number of P t ions bound prior to mineralization and to measure the distribution of species after mineralization, which provided a unique view into the mineralization process. The second illustration was a material synthesized using the cage-like protein architecture as an internal guiding synthetic scaffold for the formation of a coordination polymer core inside the protein cage. The construction of this coordination polymer was unusual in that unlike normal coordination polymer synthesis, coordination of the metal preceded formation the ditopic ligands, which were afterwards completed using azide-alkyne click chemistry. Finally, a collection of protein-polymer composites were developed, which utilized a living radical polymerization method, atom transfer radical polymerization, to form internal polymer cores. By labeling one of these protein-polymer constructs with a Gd based MRI contrast agent a material with vastly improved relaxivity was made. The development of each of these three types of composites served to improve our understanding of the natural systems, from which they are derived, and provide a basis for further development of advanced multicomponent nanomaterials.